Purple Martins struggle during wet spring

Updated: May 23, 2019

by Garrett Fodor

As the rain continues to fall, creating a wet and soggy month of May, so to are the numbers of one species of migratory bird that roosts locally.

The Purple Martin, or Progne subis, is the largest member of the swallow family in North America and they are referred to as aerial insectivores, feeding only on flying insects, which makes them popular. Since monitoring began in 1970, however, the Purple Martin population has been in a sharp decline, nearly seven percent each year, with no known reason, The Ontario Purple Martin Association notes.

The Purple Martin migrates each year from Brazil to its spring nesting home to breed. The Ontario Purple Martin Association (OPMA) believes part of the reason for the decline is environmental threats and problems along the migration route. There has been documented deforestation in the Amazon, in addition to a decrease in food availability and competition for nesting sites from invasive species, including starlings and house sparrows.

When the Purple Martins arrive in Ontario to breed, they require appropriate housing, which includes white coloured gourds or condominium-style homes in open spaces near a water source, since they like to nest together. The Martins arrive here from early to mid-April. They nest from late May to late July. They take between four and six weeks to build their nests, and it takes 26 to 32 days after hatching for fledglings to leave the nest. They then begin to migrate in August annually.

Joe Balga is the consultant to the Board for the OPMA. He believes the unpredictable weather when they nest is a reason for the decline in their numbers. He added the Martins struggle to feed in temperatures below 40 degrees Fahrenheit (4 degrees Celsius), dense fog, draught, or steady rain, due to the hard visibility and lack of insects available. Energy spent unsuccessfully forging can escalade starvation. After one day without food, it will stress. After two days, it will lose its physical condition and its wings will droop and its breastbone will become prevalent.

Balga has a colony of over 60 birds, including Purple Martins, barn swallows, and bluebirds. He has had his Martins for the last four years and has had a bluebird nest for the last five. He added that his first group of Martins arrived around the first weekend of May and that his second is delayed two weeks because of the bad weather.

With the Purple Martins struggling to feed, including this year specifically, Balga and other Purple Martin landlords have taken it upon themselves to look after their birds and to keep them from getting stressed.

Research has determined that there is supplemental feeding that can be offered to the birds that they will take and eat, while not altering their life or eating habits. Crickets and mealworms are similar to their current diet of aerial insects and something else that is offered for the birds is cooked scrambled eggs for advanced feeders. Balga said the practice for the swallows and the martins is to call them with song first, then to throw the food in the area. It requires time and practice, he said, but they will eat these food items. He added the most successful way for them to take the food is after two to three days after non-feeding.

The eggs are best accepted once the martins have taken the insects first and the eggs are the least expensive option. They are simply cooked in the microwave and cut up into small pieces and thrown up in the air for them, or placed on a platform for feeding. They will also eat off the platform, which is good for minimal effort.

Balga said platform feeding is a successful option for supplemental feeding as well, usually introduced after they take from the tossing. He said if the food items offered are thrown above the platform, it encourages them to land and eat on it. But, he added, the importance to remove eggs from it daily as they spoil. While feeding his colony around four times a day, Balga said he has gone through over 10 dozen eggs this year.

Balga and the OPMA have been involved in the community, working with the Essex Communities in Bloom Committee and the Town of Essex, to raise awareness about the birds and create housing spaces for them to roost. Through their work, they have set up a number of houses for the martins. Colonies have been installed around the Municipality of Essex, including at Colchester Harbour and the Essex Centre Sports Complex.